This invention relates in general to vehicle wheel hub mounting systems and in particular to an improved structure for such a vehicle wheel hub mounting system.
One example of a known vehicle wheel hub mounting system, indicated generally at 900, is illustrated in prior art FIG. 10. As shown therein, the prior art vehicle wheel hub mounting system 900 is associated with a driven front wheel of a vehicle and includes an axle spindle or drive shaft 912, a wheel hub 914, a bearing assembly 918, and a spanner nut 920. The axle spindle 912 includes an outer end having external threads 912A, a body having external splines 912B along a portion thereof, and an inner end (not shown) adapted to be connected to an axle (not shown) of the vehicle.
The wheel hub 914 includes internal splines 914A for receiving the mating external splines 912B of the axle spindle 912 for connecting the wheel hub 914 to the axle spindle 912 for rotation therewith. The wheel hub 914 also includes a generally radially outwardly extending flange 914B, and a bearing seat 914D. The wheel hub flange 914B includes a plurality of circumferentially spaced stud receiving holes 914C formed therein (only one of such stud receiving holes 914C is illustrated in FIG. 10). The stud receiving holes 914C are adapted to receive studs (not shown) and nuts (not shown) for securing a rotatable brake component, such as for example a brake rotor (not shown) or a brake drum (not shown), and a vehicle wheel (not shown), to the wheel hub 914 for rotation therewith. The bearing seat 914D is adapted to support the bearing assembly 918 which is in turn, secured to a non-rotatable component of the vehicle (not shown), so as to rotatably support the axle spindle 912 and the wheel hub 914 relative thereto. To secure the axle spindle 912 and the wheel hub 914 together for rotation with one another and also to preload the bearing assembly 918, the spanner nut 920 is installed on the threaded outer end 912A of the axle spindle 912 and tightened to preload the bearing assembly 918 to a predetermined load.
The vehicle wheel hub mounting system 900 is subjected to various loads during vehicle operation. Typically, the loads which the vehicle wheel hub mounting system 900 is subjected to include radial loads, bending loads, and torsional loads. Depending on the magnitude of the associated loads, the spanner nut 920 can rotate from its installed position resulting in the loss of the bearing preload provided by the spanner nut 920. Also, depending on the magnitude of the associated loads, the wheel hub 914 can move relative to the axle spindle 912 resulting in the premature wear of the respective splines 912B and 914A thereof. Thus, it would be desirable to provide an improved structure for a vehicle wheel hub mounting system which improved the retention of the spanner nut on the axle spindle and which reduced the wear of the wheel hub splines and axle spindle splines and yet was simple and inexpensive.
This invention relates to an improved vehicle wheel hub mounting system and includes a wheel hub, an axle spindle, a bearing assembly, and a threaded fastener. The wheel hub defines an axis and including a generally axially extending body having bore formed therethrough. The bore of the wheel hub includes an internal splined portion and an inner annular wheel hub surface spaced apart from the internal splined portion. The inner annular wheel hub surface defines a predetermined wheel hub inner diameter. The axle spindle is connected to the wheel hub for rotation therewith and includes a generally axially extending body having an external splined portion and an outer annular axle spindle surface spaced apart from the external splined portion. The external splined portion of the axle spindle matingly receives the internal splined portion of the wheel hub to connect the axle spindle to the wheel hub for rotation therewith. The outer annular axle spindle surface of said axle spindle defines a predetermined axle spindle outer diameter which receives the inner annular wheel hub surface of the wheel hub so as to pilot and support the wheel hub thereon. The bearing assembly is pressed onto at least a portion of one of the wheel hub and the axle spindle. The bearing assembly is adapted to be secured to a non-rotatable component of the vehicle so as to rotatably support the wheel hub and the axle spindle relative thereto. The threaded fastener nut is secured to the axle spindle for preloading the bearing assembly and securing the wheel hub and the axle spindle together for rotation with one another. As a result of separating the wheel hub to axle spindle pilot, provided by the inner annular wheel hub surface being piloted and supported on the outer annular wheel hub of the axle spindle, from the axle spindle to hub connection, provided by the mating connection of the internal axle spindle splines and the external wheel hub splines, the radial loads transmitted from the wheel hub to the axle spindle are separated from the torsional loads transmitted from the wheel hub splines to the axle spindle splines thereby reducing wear of the associated splines. Also, this separation is effective to reduce the radial loads transmitted from the wheel hub to the threaded fastener. Thus, the retention of the threaded fastener on the axle spindle is improved which in turn, is effective to maintain the bearing preload.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings.